Optical lenses and methods of preparing the same, in which an active material encapsulated in resin capsules is impregnated in said lens, adjacent an optical surface thereof. The active material may be a coloring material for producing a printed color pattern in the iris or other areas of the lens, or it may be a therapeutic agent.

This invention relates to contact lenses having a color pattern simulating the natural color structure of the human iris. The invention also relates to methods of producing such lenses.
It is often desired that contact lenses be colored or tinted for various purposes. The tinting may be useful for identification purposes and also to protect the user from bright light. Lenses may also be tinted for cosmetic purposes, not only to enhance the natural coloring of the eyes, but sometimes to conceal disfigurements.
The coloring of materials of this nature has been a demanding assignment. The colorants must be incorporated without interfering with the optical properties of the final product. They must resist leaching out on storage and autoclaving, and must not undergo decomposition in the presence of reagents used in daily cleaning and sterilization of the lens material. They must not fade upon prolonged exposure to light, and they must be non-toxic and physiologically inert, as well as mechanically non-irritating. From a commercial standpoint, it is necessary that the colorants be applied in a process which is not so complex or time consuming or labor intensive as to be impractical.
A special problem arises from the fact that the natural appearance of the human iris is not a simple solid color, but consists of a patterned structure involving many shapes and colors. Therefore, colored lenses having merely a solid color in the iris area have the disadvantage of producing an unnatural appearance when fitted in the eye.
U.S. Pat. No. 4,640,805 discloses a method in which color is applied to the lens during the manufacturing process, and spin casting techniques are used for accurately limiting the application of colorant to the iris area. However, the coloring material is dissolved into the monomer material as a solid color, without any attempt to match the natural color pattern of the human iris. U.S. Pat. No. 4,252,431 discloses a method of ensuring color only in the iris area and not in the white periphery, by separately preparing and assembling a tinted central core and a clear outer lens element. However, here again, the tinted central core is provided with a solid color, without the simulation of the natural iris pattern.
In U.S. Pat. Nos. 4,582,402 and 4,704,017, water-insoluble opaque pigment particles are deposited on the lens surface in the iris area, in a pattern designed to simulate the natural structure of the iris, using offset pad printing techniques. However, in the process disclosed in these patents, the lens must first by produced, and then, in an added manufacturing segment, the pigment pattern is prepared and transferred to the surface of the previously prepared lens. Following this, the lens is subjected to further treatment to fix the pigment to the surface of the lens and render it resistant to leaching, abrasion, fading, and the like. U.S. Pat. No. 4,668,240 also discloses a process in which a coloring substance and a binding agent are printed in an iris pattern on the surface of a contact lens. Here again, however, the lens must be first produced, and the printing is accomplished in a series of additional steps in a later manufacturing segment.
It is an object of the present invention to provide a process in which a single- or multi-colored pattern is printed and fixed in the lens during the actual manufacture of the lens itself, thus enabling significant reductions in manufacturing time as well as costs of labor and materials.
It is another object of the invention to provide an optical lens in which the printed pattern becomes a part of, and is protected by the lens matrix, adjacent the surface of the lens.
It is a further object of the invention to provide an optical lens in which the printed pattern exhibits superior resistance to ocular fluids, bleaches, hydrogen peroxide, boiling water and other chemicals, such as alcohol, acetone and freon, which come in contact with the lens during manufacturing finishing steps or daily maintenance of the lens.
A still further object of the invention is to provide a optical lens in which an active material other than a coloring material (e.g., a therapeutic agent) is fixed in the lens during the actual manufacture of the lens itself, using the special procedures disclosed hereinafter.
Other objects and advantages will be apparent from the following description and examples.
This invention is based on the surprising discovery that a highly effective colored printed pattern, such as an iris pattern, can be applied to an optical lens in the course of producing the lens itself. It has been found that, by using a specially prepared color dispersion to imprint a pattern on one or both surfaces of the lens casting mold and then proceeding with the usual steps of filling the mold with monomer, polymerizing, and finishing, it is possible to produce a optical lens having a high quality pattern embedded in the lens matrix adjacent its surface. Applying the pattern in this manner not only improves the preciseness and reproductibility of the manufacturing process but also enhances the quality of the end product. Further, applying the printed pattern to the casting mold permits the coloring step to be incorporated as an integral part of the manufacturing process, rather than reserving it as a separate, subsequent manufacturing operation. The discovery therefore significantly reduces repetitive handling of the plastic lens materials and enables efficient automation of the complete operation. The coloring agents which have been found useful in the foregoing are insoluble pigments or dyes which are dispersed in a resin system.
The invention therefore may be described in general terms as a method of producing a colored contact lens comprising the steps of selecting a coloring material which is insoluble in the monomer material to be used in the lens, dispersing the coloring material in a resin system which is compatible with the monomer material, using the resulting dispersion to imprint a pattern on one or more surfaces of a casting mold in contact with the imprinted surface or surfaces, and polymerizing the liquid to produce a lens blank having a colored pattern impregnated in said blank, adjacent one or both optical surfaces thereof.
A preferred embodiment of the invention is a method of producing a colored soft contact lens comprising the steps of providing a resin system by dissolving from about 10 to 30% by weight of a thermoplastic resin, such as polyvinyl alcohol, in about 90 to 70% by weight of a solvent, such as butanol; dispersing in the resulting solution from about 1 to 80% by weight of insoluble pigments, such as phthalocyanine blue, phthalocyanine green, titanium dioxide, iron oxides, or mixtures thereof; using the resulting dispersion to imprint an iris pattern on one or both surfaces of a casting mold; introducing a hydrogel-producing monomer, such as hydroxy ethyl methacrylate monomer, in the mold in contact with the imprinted mold surface or surfaces; and polymerizing the monomer to produce a lens blank having a colored iris pattern impregnated in the blank, adjacent one or both optical surfaces thereof.
Another embodiment of the invention comprises marking both sides of a lens blank with matching white and colored dots or rings, such that the white dot with the white sclera on the outer convex side of the lens, while the colored dot or indicia shows on the inner or concave side of the lens, to assist the wearer in determining whether the flexible lens has turned inside out (i.e., whether the lens has the proper vertiness).
The invention also comprises a new productxe2x80x94namely, an optical lens having an active material encapsulated in resin capsules impregnated in the lens, adjacent one or both optical surfaces thereof. For the purposes of this specification, the term xe2x80x9cactive materialxe2x80x9d includes (1) insoluble materials that provide color in the lens or a means of controlling radiation, such as UV radiation or (2) soluble therapeutic agents.
In the practice of the invention, the procedure is initiated by dissolving a resin in a solvent and then dispersing an insoluble pigment or dye in the resulting solution to produce a special coloring liquid, or ink, which may be used to print a pattern on the casting mold surface.
The resin may be any plastic material which is compatible with the monomer which is to be used to form the lens. It must be compatible with the monomer in the sense that it will not cause haziness, precipitation or agglomerization when it comes in contact with the lens material, or cause warping of the lens, or otherwise have an adverse impact on the optical integrity of the lens. Of course, it is also essential that the resin be non-toxic and non-irritating.
Resins suitable for use in the invention include thermoplastic materials. Materials of this type which have been found especially useful are polyvinyl alcohol and polymethylmethacrylate. Other suitable materials include polyvinylpyrrolidone, polyvinylchloride, cellulosic resins, thermoplastic polyesters, polyhydroxyethyl methacrylate, polydimethylacrylamide, and the like. Thermosetting resins in the precursor stage prior to crosslinking or setting may also be employed. For example, unsaturated polyesters may be used prior to the time they are crosslinked with styrene to form the thermoset product. Naturally occurring resins may also be used.
Any suitable solvent may be used for bringing the resin material into solution. Depending on the solubility characteristics of the resin, solvents such as alcohol, methylethylketone, acetone, cyclohexanone, and Cellosolve Acetate (2-ethoxyethyl acetate) are useful in the procedure.
The concentration of the resin in the solvent is not critical. Generally, the objective is to prepare a solution having a viscosity sufficiently low to disperse the coloring materials and other additives to be incorporated in the ink. Usually, a concentration of about 1 to 90% by weight of the resin in the solvent will be suitable. A preferred concentration is in the range of 1 to 35%. The most preferred is in the range of 1 to 10%.
The solution prepared as above is then mixed with the coloring material to prepare a suitable dispersion. The coloring material may be any colorant which is insoluble in the monomer to be used to form the lens. Preferred colorants include phthalocyanine blue, phthalocyanine green, chromic-alumina-cobaltous oxide, chromium oxides, and various iron oxides for red, yellow, brown and black colors. Opaquing agents such as titanium dioxide may also be included. For most applications, it is desirable to employ a mixture of colors, for better simulation of natural iris appearance. Although pigments are the preferred form of colorant, it is also possible to use dyes which are insoluble in the monomer lens material and which can be dispersed in the polymerized resin.
The concentration of the colorant added to the resin solution is governed by the intensity and type of the colorant. The objective is to add sufficient pigment or dye to give optimum hiding power when applied in a printing film thickness of about 10 to 40 microns. Generally, the colorant may be added in concentrations of about 1 to 80% by weight of the resin solution.
The dispersion of the colorant in the resin solution is achieved by conventional means, such as vigorously mixing in a high speed blender or milling in a roll or ball mill or by use of an ultrasonic probe. The milling and dispersion are continued until the mixture is uniform and the size of the particles has been reduced to 10 microns or below. The addition of ingredients and the dispersing techniques are carried out with the objective of preparing a printing ink with suitable viscosity for use in the subsequent offset printing operation. If necessary, conventional thixotropic agents can be added at this stage to provide the necessary sag resistance, or otherwise impart a thixotropic index sufficiently high to prevent running of the ink when subsequently applied to the surface of the casting mold.
As the next step, the above printing dispersion is used to imprint a pattern (such as that of the iris) on one or both surfaces of the casting mold which is to be used for producing the lens. The pattern is created by etching on a steel plate using well known etching techniques, and then a commercially available pad transfer printing machine is used to apply the pattern to the mold surface. The patter on the steel plate may be generated by computer design and consists of an arrangement of etched impressions, in which the intensity of the finished color may be controlled by the frequency and depth of the impressions. The etching is accomplished by applying to the steel plate a solution of material which insolubilizes when exposed to light; covering the plate with the pattern matrix; exposing the plate to light to insolubilize the areas not covered by the pattern; washing away the soluble areas; and then etching the remaining areas to the desired depths.
In the operation of the pad transfer printing machine, a doctor blade smears the ink on the steel plate, and then a silicon pad is applied to pick up the ink pattern and transfer it to the casting mold surface. In the preferred embodiment, the pattern is applied to the convex mold component, although it is possible also to apply it to the concave component, or to both. If the lens is being prepared by a technique in which only one optical surface is produced in a casting mold, and the other surface prepared by lathing, the objectives of the present invention can accomplished by applying the pattern to the single surface utilized in the casting mold. If desired, the printing procedure may be repeated using different colors or different patterns, to achieve the desired color or intensity. It is understood that the pattern may also be applied to the mold surface by other printing techniques, such as jet spray, sild screen or laser printing including liquid crystal shutters.
When the pattern has been imprinted on the casting mold surface or surfaces, as above, the solvent in the ink may be allowed to evaporate, leaving on the mold surface a deposition in which the insoluble colorant particles are encapsulated in the resin. The monomer to be used to form the lens is then poured into the mold, together with suitable conventional curing catalysts. It is a surprising feature of the present invention that, when the monomer is thus introduced, it causes a mechanical altering and softening of the surface of the individual resin/colorant capsules, which allows the monomer to penetrate the interstices between the capsules and surround them, so that the capsules become impregnated in the monomer matrix with the pattern remaining intact. As an extension of this phenomenon, a thin layer of monomer interposes itself between the resin/colorant capsules and the casting mold surface, so that when the finished lens is subsequently removed from the mold, the surface is a substantially intact layer of lens forming material, with the printed pattern of resin/colorant capsules located beneath said surface, but closely adjacent thereto.
The monomer casting liquid which is poured into the mold as above may be any of the conventional monomers or mixtures thereof which are known in the art for the production of plastic contact lenses. For example, in the area of soft contact lenses, the hydroxyethylmethacrylate and ethylene glycol dimethacrylate monomer mixtures described in U.S. Pat. No. 2,976,576 and Re. 27,401 may be used, as well as the hydroxyalkyl methacrylates and vinyl pyrrolidone described in U.S. Pat. No. 3,503,393. Specific suitable monomer materials include 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, glycerol methacrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, acrylic acid, methacrylic acid, collagen, acrylamide, diacetone acrylamide, and the like. Included also are monomeric materials resulting in polymers such as tefilcon, phemfilcon, hefilcon A, hefilcon B, perfilcon A, lidofilcon B, tetrafilcon A, droxifilcon A, ocufilcon B, Bufilcon A, crofilcon A, deltafilcon A, netrafilcon A, and etafilcon A. These are United States approved drug names (USAN).
The lens forming monomer may also be selected from the type used to produce rigid lenses, particulary gas permeable rigid lenses. Examples include hydrophobic acrylic-type polymers such as polymethyl methacrylate. The lens forming monomer may also be selected from elastomeric materials as polysiloxane.
As the next step, polymerization of the monomer liquid is initiated and completed under appropriate known curing conditions, which include curing in an oven or the use of other techniques such as radiation, including U.V. and microwave, or the use of a bath with a heat transfer fluid, such as water and silicone oil.
Following this, the lens is dismounted from the mold and then finished in the usual fashion. In the case of soft hydrogel lenses, the finishing will include customary hydrating techniques. Finally, the lens is scrutinized by quality control procedures, and the final product is then ready for packaging and labeling.
It is a feature of the present invention that the imprinting of the pattern is carried out as an integral part of the lens forming operation. After the lens material has been poured and cured, there is no further manufacturing segment in which the lens blank must be rehandled for the purpose of applying the colorant pattern. It is a further feature that the pattern is fixedly impregnated within the lens matrix, so that the color pattern is protected against leaching and exhibits superior appearance, color retention and durability.
In a further embodiment of the invention, the procedure described above may be used to place an identifying colored dot or mark adjacent the concave surface of a soft optical lens. Soft lenses have a tendency at times to turn inside-out on themselves, and it is important, but sometimes difficult, for the user to determine whether or not this has happened. A colored dot visible on the concave surface, but not on the convex, provides a readily ascertainable identification of the appropriate surface to be applied against the eye. In accordance with the present invention, such a mark can be imprinted on the surface of the mold component for the concave side of the lens and then covered by the imprinting of subsequent coloring layers, so that in the finished lens the identifying mark can be seen prior to placing in the eye, but not thereafter. Other approaches may be visualized, such as printing a colored mark on the concave side of the lens portion covering the white of the eye, and then printing a matching white spot on the convex side of the lens, to mask the colored mark.
In a further embodiment of the invention, the procedure described above may be used to place a layer of an aqueous soluble therapeutic agent or an encapsulated aqueous soluble therapeutic agent adjacent to a surface of a soft contact lens. The system may be designed to provide for the optimum controlled and prolonged release of the therapeutic agent. Such therapeutic agents include, but are not limited to, pilocarpine, epinephrine, chromolyn sodium and idoxuridine.
The following examples describe specific embodiments which are illustrative of the invention but should not be interpreted as limiting the scope of the invention in any manner. All parts and percentages are by weight unless otherwise specified.

Colored contact lenses and method of making same


Microscopic beads or other structures are attached to nucleic acids (DNA) using a terminal transferase. The transferase adds labeled dideoxy nucleotide bases to the ends of linear strands of DNA. The labels, such as the antigens digoxigenin and biotin, bind to the antibody compounds or other appropriate complementary ligands, which are bound to the microscopic beads or other support structures. The method does not require the synthesis of a synthetic oligonucleotide probe. The method can be used to tag or label DNA even when the DNA has an unknown sequence, has blunt ends, or is a very large fragment (e.g.,  greater than 500 kilobase pairs).

1. Field of the Invention
This invention relates to a method for attaching nucleic acids, such as DNA, to microscopic beads or other support structures using a terminal transferase.
2. Description of Related Art
Recent technical advancements in nanomanipulation have allowed the mechanical behavior of single DNA molecules to be studied. These techniques include the use of microspheres, magnetic beads, microfibers, microneedles, optical traps, and hydrodynamic flow. The attachment of microspheres to DNA has proven useful to manipulate DNA for placement or immobilization on a selected substrate or mechanical support, where the DNA strand can be confined in an extended conformation. Once the DNA is affixed to a substrate, a variety of processes (e.g., laser tweezers, scanning probe microscopy) can be used to sequence or map gene locations of the DNA. In addition, tethering microspheres to DNA may be useful in purification or separation methods that selectively isolate labeled or tagged DNA fragments.
Conventional techniques of tethering or attaching DNA to microspheres rely on hybridization and ligation of manufactured, labeled single-stranded DNA probes to known DNA sequences. U.S. Pat. No. 5,674,743 to Ulmer discusses methods in the art for attaching the DNA to a microscopic bead and is incorporated herein by reference. One method is to first couple specific oligonucleotide linkers to the bead using known techniques, and then to use DNA ligase to link the DNA to the linker on the bead. Oligonucleotide linkers can be employed which specifically hybridize to unique sequences at the end of the DNA fragment, such as the overlapping end from a restriction enzyme site or the xe2x80x9csticky endsxe2x80x9d of bacteriophage lambda based cloning vectors.
Another method for coupling DNA to beads uses specific ligands attached to the end of the DNA to link to ligand-binding molecules attached to the bead. Possible ligand-binding partner pairs include biotin-avidin/streptavidin, or various antibody/antigen pairs such as digoxygenin-antidigoxygenin antibody (Smith et al., xe2x80x9cDirect Mechanical Measurements of the Elasticity of Single DNA Molecules by Using Magnetic Beads,xe2x80x9d Science 258:1122-1126 (1992)). Smith et al. (1992) describe the attachment of the ends of Lambda DNA fragments to magnetic beads and glass plates using ligated 97-kbp dimers of methylated phage DNA. The left sticky end of the dimer is hybridized and ligated to a 12-base oligo, 3xe2x80x2 end-labeled previously with digoxigenin. The right sticky end is similarly attached to a 12-base oligo constructed with a 3xe2x80x2 biotin end-label. The glass plates and beads were then labeled with antidigoxygenin and avidin/streptavidin, respectively. In this procedure, the sticky ends of the dimer are known, and the fragment of DNA is relatively small. Individual multimer of xcex DNA (48.5 kbp) were chemically attached by one of their ends to a glass slide and by their other end to a magnetic bead. Ligated 97-kbp dimers of methylated phage xcex DNA, strain c1857ind1Sam7(NEB) were used. The left sticky end of the dimer is hybridized and ligated to a 12-base oligo. 3xe2x80x2 end-labeled previously with digoxigenin (Boehringer Genius-5). The right sticky end is similarly attached to a 12-base oligo constructed with a 3xe2x80x2 biotin end-label (Glenn Research). The glass microscope slide is successively coated with xcex3-aminopropyltriethoxysilane (Pierce), protein A, polyclonal antidigoxigenin (Boehringer), and finally cross-linked with dimethyl pimelimidate (Pierce). The molecule ends were labeled differently to prevent attachment of both ends of the DNA to either the glass of the bead. The DNA is free to swivel about either point of attachment.
In Baumann et al., xe2x80x9cIonic effects on the elasticity of single DNA moleculesxe2x80x9d, Proc. Natl. Acad. Sci. USA 94:6185-6190 (1997), lambda phage DNA molecules are tethered between two streptavidin-coated latex beads (d=3.5 xcexcm). One bead is held by a micropipette while the other is optically trapped by force-measuring laser tweezers. The 5xe2x80x2-overhangs of xcex DNA were biotinylated with the Klenow fragment of DNA polymerase using biotin-11-dCTP (Sigma), dATP, dGTP, and dUTP. The Klenow fragment is the E. coli DNA polymerase I fragment. The polymerase catalytically synthesizes new strands of DNA in vitro by moving along the preexisting single DNA strand and creating a new complementary strand by incorporating single nucleotides one at a time into the new strand. xcex-DNA molecules were tethered between two streptavidin-coated latex beads (diameter b 53.54 mm). One bead was held by a micropipette while the other was optically trapped by force-measuring laser tweezers.
The 5xe2x80x2-overhangs of 1 DNA (methylated c1857ind1Sam7; New England Biolabs) were biotinylated with the Klenow fragment of DNA polymerase using biotin-11-dCTP (Sigma), dATP, dGTP, and dUTP . . . Single-strand nicks were repaired with DNA ligase. After biotinyla-tion and nick ligation, DNA stocks were stored in an EDTA-containing buffer.
In Smith et al., xe2x80x9cOverstretching B-DNA: The elastic response of individual double-stranded and single-stranded DNA moleculesxe2x80x9d, Science 271:795-799 (1996), the DNA was labeled at both ends. Two oligonucleotides were constructed: a 20-nucleotide strand complementary to the right overhand of xcex, and a 5xe2x80x2-biotinylated 8-nucleotide complementary to the remaining 8 base pairs of the 20-nucleotide fragment. These oligos were hybridized to each other and to the right end of xcex, and then ligated with T4 ligase. The left end of xcex was then biotinylated with Klenow enzyme and bio-11-dCTP. Each end of a single xcex-phage dsDNA molecule (48.5 kbp) was attached to a separate microscopic latex bead. Carboxylate-polystyrene beads (3.54 xcexcm in diameter, CV=2.7%, Spherotech) were covalently coated with streptavidin using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC). Each molecule was pulled both right and left from the pipette to determine the point of attachment of the molecule on the pipette bead. DNA molecules are compact random coils in solution except when one attaches by an end to the bead on the pipette tip. Extra beads are carried by buffer and one is caught by the laser trap.
In Strick et al., xe2x80x9cBehavior of Supercoiled DNAxe2x80x9d, Biophysical Jour. 74:2016-2028 (1998), linear DNA molecules (60-kb) were bound to strepavidin-coated superparamagnetic beads. A segment of photochemically labeled DNA was affixed to each end of a 48.5-kb phage xcex DNA. A 5-kb fragment tagged roughly every 200-400-bp with a biotin label was annealed and ligated to the cohesive left end of the xcex-DNA with T4 DNA ligase. A 6-kb fragment was similarly tagged with digoxigenin molecules, and then annealed and ligated to the cohesive right end of the xcex-DNA. Fifty micrograms of phage 1-DNA (Boehringer-Mannheim, Meylan, France) are recipitated and resuspended in distilled water to eliminate any organic buffers. Two batches of this DNA are aliquoted; the first is subjected to two successive rounds of photolabeling in the presence of 25 mg of photoactivatable biotin (Pierce, Montlucon, France). Photolabeling reactions are carried out according to the Pierce protocol: DNA at a concentration of 1 mg/ml is mixed with an equal volume of photobiotin (also at a concentration of 1 mg/ml). The reaction tube is left open and placed in an ice bath, 10 cm away from a 40-W, 360-nm sunlamp for 10 min. The process is repeated, with the addition of another 25 ml of photobiotin. A second aliquot of purified DNA is subjected to the same sequence of labeling reactions, except that photoactivatable digoxigenin (Boehringer-Mannheim) is used as the labeling molecule. Both batches of labeled DNA are then precipitated in cold ethanol and resuspended in Tris-HCl (10 mM) and EDTA (1 mM) (T10 E1). They are then digested by 10 units of restriction enzyme Nru1 (New England Biolabs, Montignyle-Bretonneux, France) at 37xc2x0 C. in the enzyme""s buffer. The cohesive left (4600 bp) and cohesive right (6700 bp) fragments are isolated on an ethidium-bromide free, 0.6% agarose gel in 13 Tris-acetate-EDTA (TAE) running buffer. They are then purified with the GeneCleanII system (Bio101, France), precipitated in cold ethanol and resuspended in 10 ml of T10E1. The cohesive-left biotin-labeled fragments are then annealed for 24 h at 37xc2x0 C. to intact 1-DNA molecules suspended in T10E1 and 10 mM MgCl2, and ligated for 1 h at 37xc2x0 with 5 units of T4 DNA ligase (Boehringer-Mannheim). The cohesive-right digoxigenin-labeled fragments are annealed and ligated to the reaction product in an identical manner. The final construction is thus 59.8 kb long, with biotin and digoxigenin end-labels making up 11.3 kb.
Approximately 107 DNA molecules are incubated in 10 ml PBS with 8 ml of streptavidin-coated superparamagnetic beads (Dynal M280 or M450), previously washed three times in PBS. The reaction is stopped after 5 min by the addition of 90 ml of standard solution (10 mM PB pH 8, 0.1% Tween, 0.1 mg/ml FS DNA, and 3 mM NaN3, referred to hereafter as 10 mM PB or 10 mM phosphate buffer). Twenty microliters of that mnix is further diluted in 80 ml of standard solution and injected into the capillary tube. As the beads sediment to the capillary""s xe2x80x9cfloor,xe2x80x9d they bring the DNA molecules in contact with the antidigoxigenin-coated surface. The bead-DNA constructs are then left to incubate for at least 2 h before studies begin. We can increase the number of supercoilable (unnicked) molecules by performing a ligation reaction with T4 DNA ligase, either before or after the bead-DNA complex is injected into the capillary.
Covalent chemical attachment of the DNA to the bead can be accomplished by using standard coupling agents to link the 5xe2x80x2-phosphate on the DNA to coated microspheres through a phosphoamidate bond. In a particular embodiment in which the DNA contains the appropriate single-stranded telomeric recognition site, telomere terminal transferase (Greider et al., Cell 51:887-898 (1987)) can be used to incorporate a biotinylated nucleotide at the 3xe2x80x2 end of the DNA which can then be bound to avidin immobilized on the bead. The only substrates required for the reaction are a single-stranded telomeric sequence oligonucleotide, and dGTP plus dTTP. Repeats of the Tetrahymena telomeric sequence TTGGGG are added, 1 nucleotide at a time, onto the 3xe2x80x2 end of the input primer. A standard assay contained 20 xcexcl of a 2xc3x97reaction mix and 20 xcexcl of an enzyme fraction. The 2xc3x97reaction mix consisted of 4 xcexcl of 10xc3x97reaction buffer, 20 mM dTTP, 2 xcexcM dGTP, 0.8 xcexcg (TTGGGG)4 oligonucleotide (unless some other oligonucleotide was specified), 0.5 U of RNasin, and 1 xcexcl(10 xcexcCi of [xcex1-32P]dGTP (specific activity, 3000 Ci/mmol). The 10xc3x97reaction buffer contained 500 mM Tris (pH 8.5), 1 M sodium acetate, 20 mM MgCl2. 1 mM spermnine, 10 mM spermidine, and 50 mM 2-mercaptoethanol. After mixing the enzyme preparation to be assayed with the reaction mix, samples were incubated at 30xc2x0 C. for 60 min. In another embodiment, calf thymus terminal transferase (Kato et al., J. Biol. Chem. 242:2780 (1967)) can be used to incorporate a ligand-linked nucleotide onto the 3xe2x80x2 end of any DNA molecule with a free 3xe2x80x2 hydroxyl group. In still another approach, a DNA-binding protein can be coupled to the bead by chemistries well known in the art and in such a fashion that the DNA-binding site is unperturbed. DNA containing the recognition sequence for the DNA-binding protein can thereby be coupled to the bead. When incubations are carried out in phosphate buffer, the terminal transferase has an absolute requirement for an oligodeoxynucleotide initiator containing at least three phosphate groups and a free 3xe2x80x2 hydroxyl. Reaction mixtures (1.0 ml) contained 40 mM potassium phosphate (pH 7.0), 8 mM MgCl2, 1 mM mercaptoethanol, 2 mM dATP, 20 xcexcg of terminal transferase protein, and the 3H-labeled initiator listed. After overnight incubation at 35xc2x0, each reaction mixture was filtered through a Sephadex G-75 column (2.5xc3x9740 cm) equilibrated with 10 mM NaCl.
As an alternative to microscopic beads, bead-like structures referred to as xe2x80x9coptical handlesxe2x80x9d can be chemically synthesized at the end of a DNA molecule to provide a particle with dimensions and refractive properties appropriate for manipulation by an optical trap. The first step in the synthesis of such particle-like structures at the end of a DNA molecule can be accomplished by methods similar to those described above, with the sequential addition of branched oligonucleotides or by modification of the techniques for the synthesis of starburst dendrimers.
In general, the first step in the synthesis of an xe2x80x9coptical handlexe2x80x9d at a specific target sequence requires the binding of a bifunctional binding agent to the target sequence. The first functionality of the binding agent provides a means for uniquely recognizing and binding to the target DNA sequence. The second functionality provides a means for binding or linkage to initiate the first cycle of growth of the optical handle. Such functionality, for example, can be provided by a biotin group attached to the DNA recognition and binding functionality so as to be capable of binding to streptavidin. Adding streptavidin to the bifunctional binding agent already complexed with its target DNA sequence then results in a complex composed of target DNA, bifunctional linker-biotin, and streptavidin. Streptavidin contains four binding sites for biotin, with two each on opposite sides of the streptavidin protein molecule. Only one of these sites will be occupied by binding to the biotin group of the bifunctional linker, leaving the three other sites available for binding.
A second linker is introduced which is made of two biotin molecules joined by a spacer. The spacer couples the two biotin groups in such a way that each biotin is fully capable of binding to streptavidin, but the length and rigidity of the spacer is selected so that both biotin groups cannot bind to the same streptavidin molecule. Addition of biotin-spacer-biotin to the complex will result in the binding of one, two or three such molecules to the previously unoccupied sites in the single streptavidin molecule, providing one, two or three exposed biotin groups for subsequent binding to additional streptavidin molecules. By alternating the addition of streptavidin and biotin-spacer-biotin, the optical handle is synthesized as an exponentially growing complex of cross-linked streptavidin molecules. A sufficient number of cycles are carried out to provide an optical handle of sufficient size and optical properties for manipulation by optical tweezers.
One of the disadvantages of the above techniques for attaching DNA to microscopic beads or other structures is that the sequence at the end of the DNA fragment must be known in order to synthesize an oligonucleotide linker or probe. Thus, completely unknown DNA fragments cannot be attached to microspheres or supports using these methods. In addition, if small ( less than 18 bp) synthesized oligonucleotides are used, these oligonucleotides can attach to the targeted sequence within large DNA fragments, e.g.,  greater than 500-kb, not just at the ends. Finally, the hybridization attachment methods are limited to DNA fragments with cohesive, single-strand ends.
The present invention addresses the above-mentioned problems and provides a simple method for attaching microscopic beads and other particle-like (e.g., optical handles) or support structures to fragments of DNA of unknown sequences, of any length, and having either single-stranded or blunt (double-stranded) ends. The present method is capable of labeling both ends of the double-stranded DNA, differentiating one end from the other, and labeling the ends independently of sequence and regardless of 3xe2x80x2 or 5xe2x80x2 recessive ends. The present invention also provides for a covalent tethering of both DNA ends with an appropriate cross-linker and does not require the synthesis of a synthetic oligonucleotide probe.
The object of the invention is to attach nucleic acids, specifically DNA, to microscopic beads or other support structures using a terminal transferase. The present invention accomplishes this attachment without the synthesis of oligonucleotide probes or known target oligonucleotide or amino acid sequences.
In the present method, DNA is placed in solution with labeled dideoxy nucleotide bases. Nucleotides with antigen labels such as digoxigenin and biotin may be used. When linear double-stranded DNA is present, terminal transferase is added, which attaches a single labeled base to each of the 3xe2x80x2 ends of the DNA strands. When two different labeled bases are used (e.g., digoxigenin and biotin), the yield of DNA strands with different labels on the ends is predictably 50%. The differently labeled ends prevent both ends of a single DNA molecule from attaching to a single support structure. The labeled DNA is attached to the microscopic beads or other support structures, which are labeled with the appropriate antibody (e.g., anti-digoxigenin or avidin/streptavidin) or other complementary ligand.
Another object of the present invention is to provide a method that can be used with DNA strands having blunt (double-stranded) or single-stranded (cohesive, sticky) ends. Furthermore, the invention can attach microscopic beads, bead-like structures such as optical handles, or other support structures to DNA of any size, including fragments greater than 500 kilobase pairs (kb).
Other objects, features, and advantages of the present invention will become apparent from the following description and accompanying drawings.
The present invention is a method for attaching microscopic beads or other structures to nucleic acids using a terminal transferase. The present method is particularly useful for attaching microscopic structures to DNA. The microscopic structures include microspheres and microscopic beads made from latex, polystyrene, and magnetic or paramagnetic materials. Other structures include substrates made of glass, mica, or silicon materials. The present method can be used to tag or label DNA even when the DNA has an unknown sequence, or is very large (e.g.,  greater than 500 kilobase pairs). The present invention does not require the synthesis of a synthetic oligonucleotide probe.
In the present method, DNA is added to a buffered solution containing labeled dideoxy nucleotide bases, an enzyme, and the salts and metals needed for the enzyme to be chemically active. The bases are typically labeled in equal molar amounts with two different labels, such as the antigens digoxigenin and biotin. The labels can bind to the antibody compound (e.g., anti-digoxigenin or avidin/streptavidin) or other appropriate complementary ligand to form a tight or strong bond. The antibodies or ligands are bound to the microscopic beads or support structures by methods known in the art. Two different labels are typically used so that both ends of the DNA strand do not attach to the microscopic bead or other support structure. Many types of labels can be used: fluorescent labels, bioreactive labels, chemiluminescent labels, photolabile labels, photoreactive labels, radioactive labels, and chemically reactive labels.
When linear double-stranded DNA is formed, such as by heating, terminal transferase is added to the DNA solution. Terminal transferase is a calf thymus enzyme that adds one labeled nucleotide to each 3xe2x80x2 end of the DNA strands and provides a method for creating cohesive ends on blunt-ended DNA fragments. The labeled nucleotide is added independent of sequence or whether the strands have overhangs (single-stranded) or blunt (double-stranded) ends. Since the nucleotides add randomly to the ends, the two labels have equal probability of attaching to each end. Thus, fifty percent of the labeled DNA strands have different labels at the ends.
Since the transferase adds the bases at the ends of the DNA strands, there is labeling along the strand unless there is a break in the DNA. The present invention can easily be used with large DNA sequences, for example, greater than 500 kb. This lack of xe2x80x9cintra-strandxe2x80x9d labeling can be a distinct advantage of the present invention over conventional techniques. Conventional techniques that depend on hybridizing short oligonucleotide sequences (5-20 bases) that can occur (be repeated) elsewhere along the strand (as well as at the end) may result in undesirable intra-strand labeling. Indeed, the longer the DNA sequence and the shorter the synthesized oligonucleotide (e.g.,  less than 18 bp), the more likely the target sequence will be present within the molecule. Thus, conventional techniques may produce unsatisfactory results with large DNA sequences.
After the reaction is completed, the excess nucleotides are removed and the DNA is purified of the label. The 50% yield of DNA strands that have the same label on both ends are removed by binding the strands first to beads or resin with avidin and washing off with biotin. The beads (or resin) are then bound with antibody to digoxigenin. Only those strands having both (different) labels will bind the second time. The dual-labeled DNA is then mixed with the microscopic beads or other support structures that are coated or otherwise bound to the complementary ligand. The end of each DNA strand with the complementary ligand forms a covalent bond with bead or support structure. The non-attached end of the DNA, having a different label, can then be attached to microscopic beads or support structures that are coated or otherwise bound to a second complementary ligand.

The Regents of the University of California


Pickering emulsions, which are finely disperse systems of the water-in-oil or oil-in-water type, comprising

The present invention relates to emulsifier-free finely disperse systems of the oil-in-water and water-in-oil type, preferably as cosmetic or dermatological preparations.
Emulsions are generally taken to mean heterogeneous systems which consist of two liquids which are immiscible or have only limited miscibility with one another, which are usually referred to as phases. In an emulsion, one of the two liquids is dispersed in the form of very fine droplets in the other liquid.
If the two liquids are water and oil and if oil droplets are finely dispersed in water, then this is an oil-in-water emulsion (O/W emulsion, e.g. milk). The basic character of an O/W emulsion is defined by the water. In a water-in-oil emulsion (W/O emulsion, e.g. butter), the principle is reversed, the basic character here being determined by the oil.
In order to achieve permanent dispersion of one liquid in another, emulsions in the traditional sense require the addition of an interface-active substance (emulsifier). Emulsifiers have an amphiphilic molecular structure, consisting of a polar (hydrophilic) and a nonpolar (lipophilic) molecular moiety, which are spatially separate from one another. In simple emulsions, finely disperse droplets of one phase, surrounded by an emulsifier shell, (water droplets in W/O emulsions or lipid vesicles in O/W emulsions) are present in the second phase. Emulsifiers lower the interfacial tension between the phases by positioning themselves at the interface between two liquids. At the phase boundary, they form oil/water interfacial films, which prevent irreversible coalescence of the droplets. Emulsions are frequently stabilized using emulsifier mixtures.
Traditional emulsifiers can, depending on their hydrophilic molecular moiety, be divided into ionic (anionic, cationic and amphoteric) and nonionic:
The most well-known example of an anionic emulsifier is soap, which is usually the term used for the water-soluble sodium or potassium salts of saturated or unsaturated higher fatty acids.
Important examples of cationic emulsifiers are quaternary ammonium compounds.
The hydrophilic molecular moiety of nonionic emulsifiers frequently consists of glycerol, polyglycerol, sorbitans, carbohydrates and polyoxyethylene glycols, and, in most cases, is linked to the lipophilic molecular moiety via ester and ether bonds. The lipophilic molecular moiety usually consists of fatty alcohols, fatty acids or isofatty acids.
By varying the structure and the size of the polar and nonpolar molecular moiety, the lipophilicity and hydrophilicity of emulsifiers can be varied within wide limits.
A decisive factor for the stability of an emulsion is the correct choice of emulsifiers. The characteristics of all substances present in the system are to be taken into consideration here. In the case of, for example, skincare emulsions, polar oil components and, for example, UV filters lead to instability. As well as the emulsifiers, therefore, other stabilizers are also used which, for example, increase the viscosity of the emulsion and/or act as protective colloid.
Emulsions are an important type of product in the field of cosmetic and/or dermatological preparations.
Cosmetic preparations are essentially used for skin care. The main aim of skin care in the cosmetics sense is to strengthen or rebuild the skin""s natural function as a barrier against environmental influences (e.g. dirt, chemicals, microorganisms) and against the loss of endogenous substances (e.g. water, natural fats, electrolytes). If this function becomes impaired, increased resorption of toxic or allergenic substances or attack by microorganisms may result, leading to toxic or allergic skin reactions.
Another aim of skin care is to compensate for the loss by the skin of lipids and water caused by daily washing. This is particularly important if the natural regeneration ability is inadequate. Furthermore, skincare products should protect against environmental influences, in particular against sun and wind, and delay skin ageing.
Cosmetic preparations are also used as deodorants. Such formulations are used to control body odour, which is produced when fresh perspiration, which is in itself odourless, is decomposed by microorganisms.
Medicinal topical compositions usually comprise one or more medicaments in an effective concentration. For the sake of simplicity, in order to distinguish clearly between cosmetic and medicinal use and corresponding products, reference is made to the legal provisions in the Federal Republic of Germany (e.g. Cosmetics Directive, Foods and Drugs Act).
The use of customary emulsifiers in cosmetic or dermatological preparations is in itself acceptable. Nevertheless, emulsifiers, like ultimately any chemical substance, may in certain circumstances cause allergic reactions or reactions based on oversensitivity of the user.
For example, it is known that certain light dermatoses are triggered by certain emulsifiers, but also by various fats and simultaneous exposure to sunlight. Such light dermatoses are also called xe2x80x9cMallorca acnexe2x80x9d. There has thus been no lack of attempts to reduce the amount of customary emulsifiers to a minimum, in the ideal case even to zero.
A reduction in the required amount of emulsifier can, for example, be achieved by taking advantage of the fact that very finely divided solid particles have an additional stabilizing action. The solid substance accumulates at the oil/water phase boundary in the form of a layer, as a result of which coalescence of the disperse phases is prevented. It is not the chemical properties of the solid particles which are of fundamental importance here, but the surface properties.
Around 1910, Pickering prepared paraffin/water emulsions which were stabilized merely by the addition of various solids, such as basic copper sulphate, basic iron sulphate or other metal sulphates. This type of emulsion is thus also referred to as a Pickering emulsion.
The original forms of Pickering emulsions initially surfaced, as it were, as undesired secondary effects in a variety of industrial processes, such as, for example, in secondary oil recovery, the extraction of bitumen from tar sand and other separation processes involving two immiscible liquids and fine, dispersed solid particles. These are generally W/O emulsions which are stabilized by mineral solids. Accordingly, investigation of corresponding systems, such as, for example, the oil/water/soot or oil/water/slate dust systems was initially the focus of research activity.
Basic experiments have shown that one characteristic of a Pickering emulsion is that the solid particles are arranged at the interface between the two liquid phases, where they form, as it were, a mechanical barrier against the combining of the liquid droplets.
It is a relatively new technical development to use Pickering emulsions as a base for cosmetic or dermatological preparations.
One way of achieving solids stabilization in the sense of a pickering emulsion in a cosmetic or dermatological preparation is, according to May-Alert (Pharmazie in unserer Zeit [Pharmacy in our time], Vol. 15, 1986, No. 1, 1-7) for example, to use emulsifier mixtures which comprise both anionic and cationic surfactants. Since mixing anionic and cationic surfactants always results in the precipitation of insoluble, electroneutral compounds, deliberate precipitation of these neutral surfactants in the oil/water interface makes it possible to achieve additional solids stabilization.
European Laid-open Specification 0 686 391, moreover, describes emulsions of the water-in-oil type which are free from surface-active substances and are stabilized only by solids. Stabilization is achieved here using spherical polyalkylsilsesquioxane particles which have a diameter of from 100 nm up to 20 xcexcm. These emulsions can be referred to as Pickering emulsions according to that mentioned above.
Pickering emulsions are stabilized by the use of suitable solids or pigments. However, the preparations of the prior art generally have the disadvantage that they are limited to a narrow field of application or a restricted choice of starting materials since they can only be stably formulated in this manner. For many areas of cosmetics (e.g. for the field of face care), Pickering emulsions of the prior art have unsatisfactory cosmetic properties.
The object was therefore to remedy the disadvantages of the prior art. In particular, the intention was to provide cosmetic and dermatological bases for cosmetic and dermatological preparations which are characterized by good skin tolerability. In addition, an object of the present invention was to provide products with the widest possible variety of applications. For example, the intention was to provide bases for preparation forms such as cleansing emulsions, facecare and bodycare preparations or deodorants, but also distinctly medicinal-pharmaceutical presentations, for example preparations against acne and other skin conditions.
It was surprising and in no way predictable by the person skilled in the art that Pickering emulsions, which are finely disperse systems of the water-in-oil or oil-in-water type, comprising
(1) an oil phase which contains at least one wax and/or one oil thickener,
(2) a water phase,
(3) at least one type of microfine particles which
a) have an average particle size of less than 200 nm, which
b) display both hydrophilic and lipophilic properties, i.e. which have amphiphilic character, and are dispersible both in water and in oil and which
c) have optionally been coated on the surface and
(4) at most 0.5% by weight of one or more emulsifiers,
overcome the disadvantages of the prior art.
According to the invention, it is particularly advantageous if the preparations comprise significantly less than 0.5% by weight of one or more emulsifiers or are even entirely free from emulsifiers.
The preparations according to the invention are extremely satisfactory preparations in every respect which have considerably higher stability compared with traditional Pickering emulsions and are therefore suitable in particular to serve as bases for preparation forms having diverse application purposes. In particular, W/O Pickering emulsions within the meaning of the present invention are, surprisingly, markedly stable.
In addition, the preparations according to the invention are characterized by excellent skin tolerability. In addition, it was surprising that preparations according to the invention, which are in the form of a sunscreen, exhibit higher effectiveness than customary sunscreen formulations.
While preparations of the prior art having a pigment content of as little as 1% by weight produce a dull feel following their application to the skin, which increases further with higher pigment concentrations, the preparations according to the invention, surprisingly, do not leave a dry or dull impression on the skin, but on the contrary exhibit excellent cosmetic properties.
Although the prior art recognizes, in addition to Pickering emulsions, emulsifier-free, finely disperse cosmetic or dermatological preparations, which are generally referred to as hydrodispersions and which are dispersions of a liquid, semisolid or solid inner (discontinuous) lipid phase in an outer aqueous (continuous) phase, the prior art was unable to point the way to the present invention.
In hydrodispersions of a liquid lipid phase in an external aqueous phase, the stability can be guaranteed, for example, by building up a gel structure in the aqueous phase in which the lipid droplets are stably suspended.
German Laid-Open Specification 44 25 268 describes stable finely dispersed, emulsifier-free cosmetic or dermatological preparations of the oil-in-water type which, in addition to an oil and a water phase, contain one or more thickeners from the group consisting of the acrylic acid polymers, polysaccharides and their alkyl ethers, where for these thickeners a lowering of interfacial tension must not be measurable.
Based on similar hydrodispersions, German Laid-Open Specification 43 03 983 discloses cosmetic or dermatological sunscreen formulations which are essentially free of emulsifiers, inorganic micropigments which serve as UV filter substances being incorporated into the lipid phase of the hydrodispersion.
O/W Pickering emulsions within the meaning of the present invention, however, are obtainable by first dispersing amphilic particles according to the invention, which are suitable for the preparation of O/W Pickering emulsions, in the aqueous phase and then combining the aqueous phase with the fatty phase. W/O Pickering emulsions according to the invention, however, are obtainable by dispersing amphilic particles which are suitable for the preparation of W/O Pickering emulsions in the fatty phase.
Waxes
According to the stipulation of the German Society for Fat Economic (Fette, Seifen, Anstrichmittel, 76, 135 [1974]), as a rule the mechanicophysical properties of the waxes, which are decisive for their use, are used for the characterization of the term xe2x80x9cwaxxe2x80x9d, while the respective chemical composition remains unconsidered in the determination of the term.
xe2x80x9cWaxxe2x80x9d isxe2x80x94similarly to xe2x80x9cresinxe2x80x9dxe2x80x94a collective description of a number of natural or synthetically obtained substances, which as a rule have the following properties: kneadable at 20xc2x0 C., solid to friably hard, coarsexe2x80x94to fine-crystalline, transparent to opaque, but not glassy, melting above 40xc2x0 C. without decomposition, even slightly above the melting point of comparatively low viscosity and non-thread-drawing, strongly temperature-dependent consistency and tolerability and polishable under slight pressure. In borderline cases, if more than one of the abovementioned properties is not fulfilled in a substance, it is not a wax within the meaning of this definition. Waxes differ from similar synthetic or natural products (e.g. resins, plastic materials etc.) mainly in that as a rule they turn into the molten, low-viscosity state approximately between 50 and 90xc2x0 C., in exceptional cases also up to approximately 200xc2x0 C., and are virtually free of ash-forming compounds.
Oil thickeners are substances which, for example, are capable of absorbing liquid oils with formation of homogeneous, viscous and colloidal solutions. They are added to cosmetic or dermatological preparations during their preparation or processing in order to thicken the fatty phase.
Waxes and/or oil thickeners within the meaning of the present invention are compounds which are characterized in that, together with the other oil components of the preparations according to the invention (such as, for example, polar, liquid compounds, UV filters and their solvents etc.), they form a material which is pasty (viscous) and spreadable at room temperature, which has a viscosity of more than 5000 mPa.s at 20xc2x0 C.
Those advantageous according to the invention are, for example, natural waxes of animal and vegetable origin, such as, for example, beeswax, China wax, bumblebee wax and other insect waxes, in particular those mentioned below.
Beeswax, for example, is a secretion product from glands of honeybees, which they use for building honeycombs. Yellow (Cera flava), brown or red so-called raw wax is obtainable, for example, by melting the combs freed from the honey by centrifuging, separating the melt from solid impurities and allowing the raw wax thus obtained to solidify. The raw wax can be bleached completely white (Cera alba) by treatment with oxidizing agents.
Beeswax consists of the readily alcohol-soluble cerin, a mixture of cerotic acid CH3(CH2)24COOH and melissic acid CH3(CH2)28COOH and of an ester mixture called myricin consisting of about 70 esters of C16- to C36-acids and C24- to C36-alcohols. Essential constituents of beeswax are myricyl palmitate, myricyl cerotinate and paraffin.
Other insect waxes such as, for example, bumblebee wax, shellac wax or China wax are essentially mixtures of various esters. China wax, for example, is deposited or produced in China and Japan from the Chinese wax scale (Coccus ceriferus) living on the Chinese ash and the scale species Ceroplastes ceriferus and Ericerus pela. It is scraped from the trees and purified by remelting in boiling water. The main constituent of China wax is the cerotic acid ester of ceryl alcohol.
Shellac wax is obtained from lac, the secretion of the female lac insects (Kerria lacca), which live in huge colonies (lac is derived from the Hindi word xe2x80x9cLakhxe2x80x9d for 100,000) on trees and shrubs in Southern Asia (India, Burma, Southern China). The shellac wax accessible by solvent extraction contains myricyl alcohol, melissic acid and other wax alcohols and acids or their esters as essential constituents.
Plant waxes are also advantageous within the meaning of the present invention. Those which can preferably be used are cuticular waxes of lower and higher plants, algae, lichens, mosses and fungi, such as, for example, candelilla wax, carnauba wax, Japan wax, esparto grass wax, cork wax, rice wax, sugar cane wax, fruit waxes, e.g. apple wax, flower waxes, leaf waxes from conifers, coffee wax, flax wax, sesame wax, jojoba oil and such like.
Candelilla waxes, for example, are brownish to yellowish brown, hard waxy materials which are soluble in lipophilic solvents. Candelilla wax contains odd-number aliphatic hydrocarbons (about 42%), esters (about 39%), wax acids and wax alcohols. It can be obtained, for example, from the comminuted, fleshy leaves of a thornless spurge species (Euphorbia cerifera) by boiling with aqueous sulphuric acid.
Carnauba wax is a yellowish, greenish or dark-grey material which can be obtained in various qualities, obtained by selection from the leaves of the Brazil fan palm Copernicia prunifera or carnauba palm (Carnauba cerifera) by, for example, brushing the wax dust from the withered fronds, melting it and filtering it and, after solidification, breaking it into pieces. Carnauba wax can be lightened by bleaching. It contains about 85% of esters, in each case approximately 2-3% of free wax acids (carnaubic, behenic, lignoceric, melissic and cerotinic acid), long-chain alcohols, diols and saturated hydrocarbons.
Japan wax (also: Cera japonica) is colourless or yellowish, pure plant fat, which can be obtained, for example, in Japan from the fruits of a tree-like sumac plant (Rhus succedanea) by boiling. The main constituents of Japan wax are glyceryl palmitate and esters of japonic acid (heneicosanedioic acid, C21H40O4), phellogenic acid (docosanedioic acid, C22H42O4) and of tricosanedioic acid (C23H44O4).
Esparto wax is obtained as a by-product in pulp and paper manufacture from the esparto grass (Graminaceae) indigenous to Mediterranean countries. It consists to about 15 to 17% of wax acids (e.g. cerotic and melissic acid), to 20 to 22% of alcohols and hydrocarbons and to 63 to 65% of esters.
Particularly advantageous natural waxes within the meaning of the present invention are those obtained, for example, under the tradenames Permulgin 1550 and Permulgin 4002 from KOSTER KEUNEN and those obtainable under the tradenames Schellack Wachs 7302 L and Candellila Wachs 2039 L from the KAHL wax refinery.
Chemically modified waxes and synthetic waxes are furthermore advantageous according to the invention. Preferred modified waxes are, for example, beeswax esters, in particular the alkyl beeswaxes obtainable from KOSTER KEUNEN under the tradenames BW Ester BW 67, BW Ester BW 80.
Preferred synthetic waxes are, for example, that obtainable under the tradename beeswax component B 85 from SCHLICKUM and silicone-based waxes, such as, for example, dialkoxydimethylpolysiloxanes, which are distinguished by the following structure
in which x is a number between 18 and 24. Behenoxy dimethicone, for which x from the above structural formula is 21 and which is obtainable under the tradename Abil(copyright) Wax 2440 from Th. Goldschmidt AG is particularly advantageous. A silicone-based wax, which is obtainable under the tradename Siliconyl Beeswax from KOSTER KEUNEN is furthermore preferred according to the invention.
Further advantageous synthetic waxes are certain fatty acids and/or fatty acid mixtures, for example C16-36-fatty acids, in particular those which are obtainable under the tradename Syncrowax AW1C from Croda GmbH.
Ester waxes which are esters of
1. a saturated and/or unsaturated, branched and/or unbranched mono- and/or dicarboxylic acid having 12 to 40 carbon atoms and
2. a saturated and/or unsaturated, branched and/or unbranched alcohol having 12 to 40 carbon atoms
are moreover advantageous within the meaning of the present invention.
Ester waxes which are selected from the group listed below are particularly advantageous:
Esters of glycol, in particular glycol esters of lignoceric acid (CH3(CH2)22COOH), of cerotic acid (CH3(CH2)24COOH) and/or of montanic acid (CH3(CH2)26COOH) are furthermore advantageous. Glycol esters of montanic acid (CH3(CH2)26COOH) are very particularly advantageous within the meaning of the present invention. An advantageous glycol montanate is obtainable, for example, in a mixture with a butylene glycol montanate under the tradename Wax E Pharma from Clariant.
It is furthermore advantageous to select the wax components from the group consisting of the glycerides, in particular from the group consisting of the triglycerides. The glycerides and triglycerides listed below are particularly advantageous:
Shea butter, also called karite oil or galam butter (CAS No. 68920-03-6), is also particularly preferred. Shea butter is the fat of the seeds or kernels of the plant Butyrospermum Parkii belonging to the family of the Sapotaceae, which consists to approximately 34 to 45% by weight of solid fatty acids (principally stearic acid) and to approximately 50 to 60% by weight of liquid fatty acids (principally comprising oleic acid).
According to the invention, the waxes are furthermore preferably selected from the group consisting of the saturated and/or unsaturated, branched and/or unbranched fatty alcohols having 14 to 40 carbon atoms; behenyl alcohol (C22H45OH), cetearyl alcohol [a mixture of cetyl alcohol (C16H33OH) and stearyl alcohol (C18H37OH)], cetylarachidol[2-hexadecyl-1-eicosanol(C36H73OH], and or 2-tetradecyloctadecanol (C32H65OH) are particularly preferred. Advantageous embodiments of the two last-mentioned fatty alcohols are obtainable from Condea under the tradenames Isofol 36 and Isofol 32.
Within the meaning of the present invention, oil thickeners are selected, for example, from the group consisting of the metal soaps. Metal soaps are the salts of higher fatty acids, resin acids and naphthenic acids (stearates, palmitates, oleates, linoleates, resinates, laurates, octanoates, ricinoleates, 12-hydroxystearates, naphthenates, tallates and the like) with the exception of the sodium and potassium salts, that is, for example, the salts of the metals aluminium, barium, calcium, cadmium, cobalt, chromium, copper, iron, lithium, magnesium, manganese, nickel, lead, tin, strontium and zinc.
Of course, the person skilled in the art knows that among the metal soaps are some which would be fundamentally suitable for the realization of the present invention, but which should nevertheless be dispensed with because of harmful action on the skin or other concomitant factors. According to the CIR panel, a committee which checks whether adequate toxicity data are available for substances which are employed in the cosmetic industry (CIR: Cosmetic Ingredient Review), for example, lithium, aluminium, calcium and zinc stearates are to be regarded as harmless in the doses which are customarily used for the preparation of cosmetic compositions. In addition to the requirements of various pharmaceutical regulations, magnesium stearate also meets the demands which foodstuffs quality sets.
For the sake of simplicity, reference is made to the relevant regulations for unambiguous differentiation between cosmetically harmful and harmless substances (e.g. Cosmetics decree, Food and Drugs Act, official pharmacopoeia, publications of the CIR panel etc.).
Aluminium stearate and magnesium stearate are particularly preferred within the meaning of the present invention.
The oil thickener(s) selected from the group consisting of the layered silicates, in particular from the group consisting of the bentonites and hectorites, is/are furthermore advantageous. Bentonites are clays and rocks which contain smectites, especially montmorillonite, as the main minerals. Modified bentonites and hectorites, for example those whose organophilicity has been increased by reaction with quaternary ammonium compounds, are particularly preferred within the meaning of the present invention. These types of bentonites are also designated as organophilic bentonites or alternatively bentones. Those which are very particularly preferred are stearalkonium hectorite, a reaction product of hectorite and stearalkonium chloride (benzyldimethylstearylammonium chloride), and quaternium-18 hectorite, a reaction product of hectorite and a quaternary ammonium salt, which are obtainable from Nordmann and Rassmann, for example, under the tradenames Bentone 27 and Bentone 38.
The total amount of one or more waxes and/or oil thickeners in the finished cosmetic or dermatological preparations is advantageously chosen to be in the range of 0.5 to 20.0% by weight, preferably between 1.0 and 5.0% by weight, based on the total weight of the preparations.
It is also advantageous, although not obligatory, for the Pickering emulsions according to the invention to comprise other auxiliaries which can contribute to reducing or preventing a dull or dry feel on the skin following their application, where it is possible that the main purpose of these substances is a different one. Preferably, these substances are, for example, chosen from the group of unsymmetrically substituted s-triazine derivatives, cyclodextrins, film formers and polymeric moisturizers, it being possible for these substances to be present either individually or in a mixture.
The cosmetic properties of the Pickering emulsions according to the invention can additionally, for example, be further improved by also using oils in the oil phase which have a viscosity of less than 30 mPa.s, in particular of less than 20 mPa.s (determined using a rheometer from Contraves (Rheomat 108E) at a shear gradient of 500/s and a temperature of 25xc2x0 C.).
Microfine Particles
The amphiphilic character of the microfine particles according to the invention is evident, for example, from the fact that they are dispersible both in water and in oil.
It is advantageous to choose the average particle diameter of the particles used to be between 1 nm and 200 nm, particularly advantageously between 5 nm and 100 nm.
It is also advantageous to choose the concentration of all amphiphilic particles according to the invention to be greater than 0.1% by weight, particularly advantageously between 0.1% by weight and 30% by weight, based on the total weight of the preparations.
For the purposes of the present invention, advantageous particles are all those which are suitable for stabilizing Pickering W/O emulsions or Pickering O/W emulsions. It is essentially insignificant for the present invention in which of the potentially naturally occurring modifications the particles are present.
To stabilize the Pickering emulsions, preference is given to using untreated, virtually pure pigment particles, in particular those which can be used as dyes in the food industry and/or as absorbers of UV radiation in sunscreens. Examples of advantageous pigments are the zinc oxide pigments available from Merck which are available under the tradenames Zinkoxid neutral from Haarmann and Reimer or NanoX from Harcros Chemical Group.
For the purposes of the present invention, Pickering emulsions are likewise advantageously stabilized by inorganic pigments which have been surface-treated (xe2x80x9ccoatedxe2x80x9d) to repel water, where at the same time the intention is to form or retain the amphiphilic character. This surface-treatment can consist in providing the pigments with a thin hydrophobic layer by processes known per se.
One such process, which is described below using titanium dioxide as an example, consists in, for example, producing the hydrophobic surface layer according to the following reaction
n TiO2+m(RO)3Sixe2x80x94Rxe2x80x2xe2x86x92n TiO2(surf.).
n and m are arbitrary stoichiometric parameters, and R and Rxe2x80x2 are the desired organic radicals. Particularly advantageous are TiO2 pigments, for example those coated with aluminium stearate, available under the tradename MT 100 T from TAYCA.
A further advantageous coating of the inorganic pigments consists of dimethylpolysiloxane (also: dimethicone), a mixture of completely methylated, linear siloxane polymers which are terminally blocked with trimethylsiloxy units. For the purposes of the present invention, particularly advantageous pigments are zinc oxide pigments which are coated in this way.
Also advantageous is a coating of the inorganic pigments with a mixture of dimethylpolysiloxane, in particular dimethylpolysiloxane having an average chain length of from 200 to 350 dimethylsiloxane units, and silica gel, which is also referred to as simethicone. It is particularly advantageous if the inorganic pigments have been additionally coated with aluminium hydroxide or hydrated aluminium oxide (also: alumina, CAS No.: 1333-84-2). Particularly advantageous are titanium dioxides which have been coated with simethicone and alumina, it being possible for the coating to also comprise water. One example thereof is the titanium dioxide available under the tradename Eusolex T2000 from Merck.
For the purposes of the present invention it is also advantageous to use a mixture of different pigment types either within a crystal, for example as mixed iron oxide, or by combination of two or more pigment types within a preparation.
The Pickering emulsions are also preferably stabilized by boron nitride particles, for example by the boron nitrides listed below:
It is advantageous to choose the average particle diameter of the boron nitride particles used to be less than 20 xcexcm, particularly advantageously less than 15 xcexcm. For the purposes of the present invention, Pickering emulsions are likewise advantageously stabilized by boron nitride particles which have been surface-treated (xe2x80x9ccoatedxe2x80x9d) to repel water, where at the same time the intention is to form or retain the amphiphilic character.
An advantageous coating of the boron nitride particles consists of dimethylpolysiloxane (dimethicone). The boron nitride particles treated with dimethicone and available from Carborundum under the tradename Trxc3xa8s BN(copyright) UHP 1106 are advantageous, for example.
Also advantageous is a coating of the boron nitride particles with polymethylhydrogensiloxane, a linear polysiloxane which is also referred to as methicone. Advantageous boron nitride particles treated with methicone are, for example, those available from Carborundum under the tradename Trxc3xa8s BN(copyright) UHP 1107.
It is also advantageous to stabilize the Pickering emulsions according to the invention using microfine polymer particles.
For the purposes of the present invention, examples of advantageous microfine polymer particles are polycarbonates, polyethers, polyethylenes, polypropylenes, polyvinyl chloride, polystyrene, polyamides, polyacrylates and the like.
Advantageous according to the invention are, for example, microfine polyamide particles which are available under the tradename SP-500 from TORAY. Also advantageous are polyamide 6 (also: nylon 6) and polyamide 12 (also: nylon 12) particles. Polyamide 6 is the polyamide formed from xcex5-aminocaproic acid (6-aminohexanoic acid) or xcex5-caprolactam [poly(xcex5-caprolactam)], and polyamide 12 is a poly(xcex5-laurolactam) from xcex5-laurolactam. For the purposes of the present invention, Orgasol(copyright) 1002 (polyamide 6) and Orgasol(copyright) 2002 (polyamide 12) from ELF ATOCHEM, for example, are advantageous.
Other advantageous polymer particles are microfine polymethacrylates. Such particles are available, for example, under the tradename POLYTRAP(copyright) from DOW CHEMICAL.
It is particularly advantageous, but not obligatory, if the microfine polymer particles used have been surface-coated. This surface-treatment can consist in providing the pigments with a thin hydrophilic layer by processes known per se. Advantageous coatings consist, for example, of TiO2, ZrO2 or also other polymers, such as, for example, polymethyl methacrylate.
Particularly advantageous microfine polymer particles for the purposes of the present invention are also obtainable by the process, described in U.S. Pat. No. 4,898,913, for the hydrophilic coating of hydrophobic polymer particles.
It is advantageous to choose the average particle diameter of the microfine polymer particles used to be less than 100 xcexcm, particularly advantageously less than 50 xcexcm. In this connection, it is essentially insignificant in which form (platelets, rods, spherules, etc.) the polymer particles used are present.
In addition, it is advantageous to stabilize the Pickering emulsions according to the invention using modified polysaccharides.
For the purposes of the present invention, modified polysaccharides are, for example, obtainable by reaction of starch with mono-, bi- or polyfunctional reagents or oxidizing agents in reactions which proceed in a largely polymer-analogous manner.
Such reactions are based essentially on modifications of the hydroxyl groups of the polyglucans by etherification, esterification or selective oxidation. This produces, for example, so-called starch ethers and starch esters of the general structural formula
in which R can, for example, be a hydrogen and/or an alkyl and/or an aralkyl radical (in the case of starch ethers) or a hydrogen and/or an organic and/or inorganic acid radical (in the case of starch esters). Starch ethers and starch esters are advantageous, modified polysaccharides for the purposes of the present invention.
Particularly advantageous starch ethers are, for example, those which are obtainable by etherification of starch with tetramethylolacetylenediurea and which are referred to as non-mucilaginous starch (nonswelling starch).
Also particularly advantageous are starch esters and salts thereof, for example the sodium and/or aluminium salts of half-esters of starch which have low degrees of substitution, in particular sodium starch n-octenyl succinate of the structural formula (II) in which R is characterized by the following structure
and which is available, for example, under the tradename Amiogum(copyright) 23 from CERESTAR, and aluminium starch octenyl succinates, in particular those available under the tradenames Dry Flo(copyright) Elite LL and Dry Flo(copyright) PC from CERESTAR.
It is advantageous to choose the average particle diameter of the modified polysaccharide used to be less than 20 xcexcm, particularly advantageously less than 15 xcexcm.
The list of given modified polysaccharides which are able to stabilize Pickering emulsions according to the invention is of course not intended to be limiting. For the purposes of the present invention, modified polysaccharides are obtainable in a large number of ways known per se, both of a chemical and a physical nature.
The abovementioned amphiphilic particles are outstandingly suitable both for the stabilization of W/O Pickering emulsions and for the stabilization of O/W Pickering emulsions. Microfine particles according to the invention are mentioned below which advantageously in particular stabilize one of the two emulsion types W/O or O/W.
W/O Pickering Emulsions
The water phase proportion in the W/O Pickering emulsions according to the invention is preferably selected from the range of 0.5 to 75% by weight, based on the total weight of the formulations.
Magnesium silicates (also: talc), for example those obtainable under the tradename Talkum Micron from Grolmann, in particular are also advantageous for the stabilization of W/O Pickering emulsions.
O/W Pickerinq Emulsions
The fatty phase fraction of the O/W Pickering emulsions according to the invention is preferably selected from the range of 0.5 to 75% by weight, based on the total weight of the formulations.
Untreated, almost pure pigment particles, for example titanium dioxide pigments, in particular those which are obtainable under the tradename KRONOS(copyright) 1171 (TiO2) from Kronos Titan are also particularly advantageous for the stabilization of O/W Pickering emulsions within the meaning of the present invention.
O/W Pickering emulsions within the meaning of the present invention are furthermore particularly advantageously stabilized by metal oxide particles which are coated with aluminium hydroxide and/or silicon dioxide. Advantageous embodiments are, for example, titanium dioxide particles, which are obtainable under the name EUSOLEX(copyright) TA from Merck.
It is furthermore advantageous, although not obligatory, to combine the microfine particles according to the invention with further amphiphilic particles which can optionally also contribute to the stabilization of the Pickering emulsions.
Such particles are, for example, titanium dioxide pigments which are coated with octylsilanol, and/or silicon dioxide particles which have a water-repellent treatment on the surface. Suitable silicon dioxide particles are, for example, spherical polyalkylsilsesquioxane particles, such as are mentioned in European Laid-Open Specification 0 686 391. Such polyalkylsilsesquioxane particles are obtainable, for example, from Degussa under the tradenames Aerosil R972 and Aerosil 200V. Suitable titanium dioxide particles are likewise obtainable from Degussa under the tradename T805.
The Pickering emulsions according to the invention can serve as a base for cosmetic or dermatological formulations. These can be combined in the customary manner and serve, for example, for the treatment and care of the skin, as a lipcare product, as a deodorant product and as a make-up or make-up removal product in decorative cosmetics or as a sunscreen preparation. For use, the cosmetic and dermatological preparations according to the invention are applied to the skin in adequate amount in the manner customary for cosmetics.
Accordingly, cosmetic or topical dermatological compositions within the meaning of the present invention, depending on their make-up, can be used, for example, as a skin-protection cream, cleansing milk, sunscreen lotion, nutrient cream, day cream or night cream, etc. It is optionally possible and advantageous to use the compositions according to the invention as a base for pharmaceutical formulations.
The cosmetic and dermatological preparations according to the invention can contain cosmetic auxiliaries, such as are customarily used in such preparations, e.g. preservatives, bactericides, perfumes, substances for preventing foaming, colorants, pigments which have a colouring action, thickening agents, emollient, moisturizing and/or humectant substances, fats, oils, waxes or other customary constituents of a cosmetic or dermatological formulation such as alcohols, polyols, polymers, foam stabilizers, electrolytes, organic solvents or silicone derivatives.
Pickering emulsions according to the invention can also contain thickening agents in order to improve the tactile properties of the emulsion.
In particular, the Pickering emulsions according to the invention can also contain antioxidants. According to the invention, favourable antioxidants which can be used are all antioxidants suitable or customary for cosmetic and/or dermatological applications.
Advantageously, the antioxidants are selected from the group consisting of amino acids (e.g. glycine, histidine, tyrosine, tryptophan) and their derivatives, imidazoles (e.g. urocanic acid) and their derivatives, peptides, such as D,L-camosine, D-carnosine, L-carnosine and their derivatives (e.g. anserine), carotenoids, carotenes (e.g. xcex1-carotene, xcex2-carotene, lycopene) and their derivatives, chlorogenic acid and its derivatives, lipoic acid and its derivatives (e.g. dihydrolipoic acid), aurothioglucose, propylthiouracil and other thiols (e.g. thioredoxin, glutathione, cysteine, cystine, cystamine and their glycosyl, N-acetyl, methyl, ethyl, propyl, amyl, butyl and lauryl, palmitoyl, oleyl, xcex3-linoleyl, cholesteryl and glyceryl esters) and their salts, dilauryl thiodipropionate, distearyl thiodipropionate, thiodipropionic acid and its derivatives (esters, ethers, peptides, lipids, nucleotides, nucleosides and salts) and sulphoximine compounds (e.g. buthionine sulphoximine, homocysteine sulphoximine, buthionine sulphone, penta-, hexa- and heptathionine sulphoximine) in very small tolerable doses (e.g. pmol to xcexcmol/kg), furthermore (metal) chelators (e.g. xcex1-hydroxy fatty acids, palmitic acid, phytic acid, lactoferrin), xcex1-hydroxy acids (e.g. citric acid, lactic acid, malic acid), humic acid, bile acid, bile extracts, bilirubin, biliverdin, EDTA, EGTA and their derivatives, unsaturated fatty acids and their derivatives (e.g. xcex3-linolenic acid, linoleic acid, oleic acid), folic acid and its derivatives, ubiquinone and ubiquinol and their derivatives, vitamin C and derivatives (e.g. ascorbyl palmitate, Mg ascorbyl phosphate, ascorbyl acetate), tocopherols and derivatives (e.g. vitamin E acetate), vitamin A and derivatives (vitamin A palmitate) and coniferyl benzoate of benzoin, rutic acid and its derivatives, xcex1-glycosylrutin, ferulic acid, furfurylideneglucitol, carnosine, butyihydroxytoluene, butylhydroxyanisole, nordihydroguaiac acid, nordihydroguaiaretic acid, trihydroxybutyrophenone, uric acid and its derivatives, mannose and its derivatives, zinc and its derivatives (e.g. ZnO, ZnSO4), selenium and its derivatives (e.g. selenomethionine), stilbenes and their derivatives (e.g. stilbene oxide, trans-stilbene oxide), and the derivatives suitable according to the invention (salts, esters, ethers, sugars, nucleotides, nucleosides, peptides and lipids) of these said active compounds.
The amount of the abovementioned antioxidants (one or more compounds) in the preparations according to the invention is preferably from 0.001 to 30% by weight, particularly preferably from 0.05-20% by weight, in particular 1-10% by weight, based on the total weight of the preparation.
If vitamin E and/or its derivatives are the antioxidant(s), it is advantageous to select their respective concentrations from the range of 0.001-10% by weight, based on the total weight of the formulation.
If vitamin A, or vitamin A derivatives, or carotenes or their derivatives are the antioxidant(s), it is advantageous to select their respective concentrations from the range of 0.001-10% by weight, based on the total weight of the formulation.
Cosmetic and dermatological preparations which are present in the form of a sunscreen composition are also favourable. These preferably contain at least one UV-A filter substance and/or at least one UV-B filter substance and/or at least one further inorganic pigment from the group consisting of the oxides of iron, zirconium, silicon, manganese, aluminium, cerium and mixtures thereof and also modifications in which the oxides are the active agents.
However, it is also advantageous within the meaning of the present invention to make available those cosmetic and dermatological preparations whose main purpose is not protection from sunlight, but which nevertheless contain substances which protect against UV. Thus, UV-A and UV-B filter substances are usually incorporated, for example, into day creams.
Advantageously, preparations according to the invention can contain substances which absorb UV radiation in the UV-B range, the total amount of filter substances being, for example, 0.1% by weight to 30% by weight, preferably from 0.5 to 10% by weight, in particular 1.0 to 6.0% by weight, based on the total weight of the preparations, in order to make available cosmetic preparations which protect the hair or the skin from the entire range of ultraviolet radiation.
If the emulsions according to the invention contain UV-B filter substances, these can be oil-soluble or water-soluble. Oil-soluble UV-B filters which are advantageous according to the invention are, for example:
3-benzylidenecamphor derivatives, preferably 3-(4-methylbenzylidene)camphor, 3-benzylidenecamphor;
4-aminobenzoic acid derivatives, preferably 2-ethylhexyl 4-dimethylaminobenzoate, amyl 4-dimethylaminobenzoate;
esters of cinnamic acid, preferably 2-ethylhexyl 4-methoxycinnamate, isopentyl 4-methoxycinnamate;
esters of salicylic acid, preferably 2-ethylhexyl salicylate, 4-isopropylbenzyl salicylate, homomenthyl salicylate,
derivatives of benzophenone, preferably 2-hydroxy4-methoxybenzophenone, 2-hydroxy4-methoxy-4xe2x80x2-methylbenzophenone, 2,2xe2x80x2-dihydroxy-4-methoxybenzophenone;
esters of benzalmalonic acid, preferably di(2-ethylhexyl) 4-methoxybenzalmalonate,
triazine derivatives which are symmetrical with respect to the C3 axis of the triazine parent structure, preferably tris(2-ethylhexyl) 4,4xe2x80x2,4xe2x80x3-(1,3,5-triazine-2,4,6-triyltriimino)trisbenzoate,
benzotriazole derivatives, preferably 2,2xe2x80x2-methylenebis(6-(2H-benzotriazole-2-yl)4-(1,1 ,3,3-tetramethylbutyl)phenol)
and UV filters bonded to polymers.
Advantageous water-soluble UV-B filters are, for example:
salts of 2-phenylbenzimidazole-5-sulphonic acid such as its sodium, potassium or its triethanolammoniun salt, and the sulphonic acid itself;
sulphonic acid derivatives of benzophenones, preferably 2-hydroxy4-methoxybenzophenone-5-sulphonic acid and its salts;
sulphonic acid derivatives of 3-benzylidenecamphor, such as, for example, 4-(2-oxo-3 bornylidenemethyl)benzenesulphonic acid, 2-methyl-5-(2-oxo-3 bornylidenemethyl)sulphonic acid and its salts.
The list of the UV-B filters mentioned, which can be used in the Pickering emulsions according to the invention, should, of course, be non-limiting.
It can also be advantageous in Pickering emulsions according to the invention to use UV-A filters which have hitherto be customarily contained in cosmetic preparations. These substances are preferably derivatives of dibenzoylmethane, in particular 1-(4xe2x80x2-tert-butylphenyl)-3-(4xe2x80x2-methoxyphenyl)propane-1,3-dione and 1-phenyl-3-(4xe2x80x2-isopropylphenyl)propane-1,3-dione.
Other advantageous UV-A filter substances are phenylene-1,4-bis(2-benzimidazyl)-3,3xe2x80x2-5,5xe2x80x2-tetrasulphonic acid:
and its salts, particularly the corresponding sodium, potassium or triethanolammonium salts, in particular the bis-sodium salt of phenylene-1,4-bis(2-benzimidazyl)-3,3xe2x80x2-5,5xe2x80x2-tetrasulphonic acid:
and 1,4-di(2-oxo-10-sulfo-3-bornylidenemethyl)benzene and salts thereof (particularly the corresponding 10-sulfato compounds, in particular the corresponding sodium, potassium or triethanolammonium salt), which is also referred to as benzene-1,4-di(2-oxo-3-bornylidenemethyl-10-sulphonic acid) and is characterized by the following structure:
Preparations which contain UV-A filters are also a subject of the invention. The amounts used for the UV-B combination can be employed.
Preparations according to the invention can also be advantageously used as bases for cosmetic deodorants and antiperspirants, so that a particular embodiment of the present invention relates to Pickering emulsions as bases for cosmetic deodorants.
Cosmetic deodorants are used to control body odour which arises when fresh perspiration, which is in itself odourless, is decomposed by microorganisms. Customary cosmetic deodorants are based on various modes of action.
In antiperspirants, astringents, mainly aluminium salts, such as aluminium hydroxychloride (aluminium chlorohydrate), reduce the formation of perspiration.
The use of antimicrobial substances in cosmetic deodorants can reduce the bacterial flora of the skin. In an ideal situation, only the microorganisms which cause the odour should be effectively reduced. The flow of perspiration itself is not influenced as a result, and in ideal circumstances, only microbial decomposition of perspiration is stopped temporarily.
The combination of astringents and antimicrobial active substances in one and the same composition is also common.
All active ingredients common for deodorants or antiperspirants can advantageously be used, for example odour concealers, such as customary perfume constituents, odour absorbers, for example the phyllosilicates described in Laid-open Patent Specification DE 40 09 347, of these in particular montmorillonite, kaolinite, illite, beidellite, nontronite, saponite, hectorite, bentonite, smectite, and also, for example, zinc salts of ricinoleic acid. Antibacterial agents are also suitable to be incorporated into the novel W/O emulsion sticks. Advantageous substances are, for example, 2,4,4xe2x80x2-trichloro-2xe2x80x2-hydroxy diphenyl ether (Irgasan), 1,6-di(4-chlorophenylbiguanido)hexane (chlorhexidine), 3,4,4xe2x80x2-trichlorocarbanilide, quaternary ammonium compounds, oil of cloves, mint oil, thyme oil, triethyl citrate, farnesol (3,7,11-trimethyl-2,6,10-dodecatrien-1-ol) and also the active ingredients or active ingredient combinations described in the Laid-open Patent Specifications DE-A-37 40 186, DE-A-39 38 140, DE-A-42 04321, DE-A-42 29707, DE-A-43 09 372, DE-A-44 11 664, DE-A-195 41 967, DE-A-195 43 695, DE-A-195 43 696, DE-A-195 47 160, DE-A-196 02 108, DE-A-196 02 110, DE-A-19602111, DE-A-19631003, DE-A-19631004 and DE-A-19634019, and the Patent SSpecifications DE-42 29 737, DE-42 37 081, DE-43 24 219, DE-44 29 467, DE-44 23 410 and DE-195 16 705. Sodium hydrogencarbonate can also be used advantageously.
The list of specified active ingredients and active ingredient combinations is of course not intended to be limiting.
The amount of antiperspirant active ingredients or deodorants (one or more compounds) in the preparations is preferably from 0.01 to 30% by weight, particularly preferably from 0.1 to 20% by weight, in particular 1-10% by weight, based on the total weight of the preparation.

Emulsifier-free finely disperse systems of the oil-in-water and water-in-oil type

Abstract: (2) a water phase,

Abstract: c) have optionally been coated on the surface, and

Abstract: (4) at most 0.5 % by weight of one or more emulsifiers.


A plastisol based composition contains:. (a) a copolymer of an aliphatic olefinically unsaturated material and an anhydride containing material; and PA1 (b) a polyvinyl chloride plastisol.. The composition is particularly suitable for use as a sealant.

The present invention relates to polyvinyl chloride plastisol compositions, for example sealant compositions.
In the manufacture of automobiles, the automobile body is initially primed with a coating composition to prevent corrosion of the metal. This can be done in a number of ways although generally it is performed by cationic electrodeposition using the auto body as the cathode. Once the automobile body has been primed in this manner, subsequent steps in the assembly are carried out. These steps typically include the use of sealants over the primed automobile body. The sealants are subsequently topcoated along with the remainder of the body during the final stages of the painting process.
Polyvinyl chloride plastisols offer several advantages for use as sealant compositions: a good balance of strength, elongation and toughness, minimal to no volatile organic component and low cost. However, despite these advantageous properties, when used in conjunction with cationically electrodepositable primer compositions in automotive applications, adhesion is poor and yellowing of the topcoat composition results.
Historically, polyaminoamides which are art recognized adhesion promoters, have been utilized in an attempt to deal with the above adhesion problems. These, however, can adversely affect the stability of the plastisol based sealant composition, the cure of the topcoat and in addition, cause more yellowing.
There is a need, therefore, for a polyvinyl chloride plastisol based composition which exhibits excellent adhesion to primed metal and is capable of being topcoated with a variety of coating compositions without yellowing of the topcoat.

Polyvinyl chloride plastisol composition suitable as a sealant